The present invention relates generally to devices and methods for joining sutures together without knots, and for securing living tissue structures together without sutures.
In minimally invasive surgical procedures that use elongated instruments and videoscopic viewing of the surgery site, there is a significant elevation in the difficulty of knot tying and wound approximating. Traditional methods of wound closure routinely involve the use of individual hand-knotted sutures. The suture strands are directed through portions of tissue to be joined and formed into a single stitch, which is then knotted. However, due to the location of the area being sutured, the delicate nature of anatomical features, and the stiffness of the suture used, it can be difficult to tie uniform stitches to close the wound that do not unravel or tie off (or ligate) a vessel. Non-uniform stitches (i.e., stitches of varying tension) or varied bite size (depth into the tissue) can cause uneven healing, localized trauma, infection, and patient discomfort.
To reduce the discomfort and aid healing, it is desirable to secure sutures uniformly and close to a wound. Due to the stiffness of some sutures, knotting the sutures can be difficult, particularly when the tissue to be sutured is deep within the body. Typical knots may be relatively large and elevated above the tissue being sutured, which can increase patient discomfort.
It is also desirable in many surgical procedures where sutures are used to reduce the size of the knot bundle and the amount of foreign material in the body. The knot bundle can become an irritant and retard the healing process and cause discomfort or pain for the patient. The knot bundle can also be a source of infection.
Methods known in the art to overcome these problems include various suture securing devices such as buttons, and methods of fusing synthetic sutures. Although buttons can produce sutures with even tension and without the concomitant dexterity of knot tying, their elevated location above the wound or within the body cavity can cause irritation and discomfort. Furthermore, there is a risk of button migration, since they are discrete objects in the body.
Suture fusion techniques, whereby synthetic polymer suture strands are melted together by the application of heat or other energy to the sutures, are known in the art. Examples of devices to perform such suture fusion are disclosed in U.S. Pat. No. 5,417,700, assigned to the assignee of this application and incorporated herein by reference. However, some polymeric sutures are not amenable to this process. For example, braided or multi-filament sutures may not completely fuse since spaces between the individual strands may interfere with the heat or energy transfer needed for fusion to occur. As a result, the sutures may be incompletely fused, and the resulting joint may fail.
It would be advantageous to provide suture and tissue joining devices which are fusible to and/or around sutures and other structures, including living tissue, so as to avoid the need for suture knots.
According to one aspect of the invention, there is provided a device for securing one or more elongated members or the same elongated member looped upon itself. The device is a flexible, fusible collar that is disposed about a central region which extends about a central axis. The collar extends circumferentially between two end portions and is biasable into a nominally closed position so that the end portions of the collar overlap. In this form the collar is adapted to encircle a portion of the elongated members. The overlapping portions of the collar are adapted to fuse to each other around the elongated members upon application of sufficient energy to the overlapping portions of the collar.
In one embodiment, the elongated members are surgical sutures which are made of a fusible material. The sutures are adapted to fuse at least to each other and possibly also to the collar in a knotless weld upon application of sufficient energy to the collar.
In another embodiment, the sutures are made of non-fusible, or minimally fusible material and only the collar is providing the welded interface. In another embodiment, the sutures are made of braided material that is marginally fusible. In another embodiment, the elongated members are a band of material that encircles a bundle of other structures, such as blood vessels.
The collar is preferably made of a thermoplastic polymeric material. The elongated members can be surgical sutures which are also made of a fusible, thermoplastic polymeric material. In another embodiment, the elongated members can be living tissue structures. The energy may be generated from a variety of sources known in the art, such as for example, thermal energy, optical energy, radio-frequency energy, current sources or more preferably, ultrasonic energy.
In a preferred embodiment, the collar includes one or more energy directors extending from a surface of the collar. The energy directors define fusion regions of the sutures and the collar and are adapted to focus energy applied to the collar to the fusion regions so that the sutures and collar fuse together preferentially at the fusion regions. The energy directors can be located along the inner surface of the collar, at the opposing surfaces of the overlap region, or both.
The inside surface of the collar may also be smooth, or have protrusions, grooves or other texturing to aid in securing the encircled structures.
According to another aspect of the invention, there is provided a kit for securing one or more elongated living tissue structures. The kit includes a fusible collar as described above, and a fusing tool which compresses the collar around the tissue structures so that the tissue structures are securely retained within the collar and portions of the collar overlap. The fusing tool applies energy to the collar to fuse the overlapped portions of the collar together around the tissue structures. The fusing tool includes generally an energy source, a welding head, an end effector, and general electronics, switches, control devices and the like for supplying weld energy and activating the end effector.
In one embodiment of the fusing tool, the energy source is ultrasonic energy. The fusing tool preferably includes an ultrasonic transducer, an ultrasonic welding horn, and an end effector. The end effector may include one or more jaw members adapted for selective deployment around at least a portion of the collar to form an ultrasonic welding anvil. In various embodiments, the end effector can be a pair of opposable jaws which move with respect to each other, or a pair of jaws which are resiliently biased toward each other.
In alternate embodiments, energy for bonding is supplied by thermal energy (e.g., heat), optical energy (e.g., laser generated), electrical energy (e.g., radio frequency, RF), or current sources (e.g., resistive heating).
According to another aspect of the invention, there is provided a kit for joining a plurality of surgical sutures together without a knot. The kit provides a fusible collar as described above, and a fusing tool as described above, for compressing the collar around the sutures so that the sutures are securely retained within the collar. The fusing tool applies energy to the collar to fuse the overlapping portions of the collar to each other and may also fuse portions of the collar to portions of the sutures.
According to yet another aspect of the invention, there is provided a method for securing one or more elongated members, such as living tissue structures. A fusible collar as described above is provided. The collar encircles the elongated members to be secured, and the collar is then compressed around the elongated member or members so that portions of the collar overlap. Energy is applied to the overlapped portions of the collar while it is compressed so that the overlapped portions are fused together around the elongated structures. The method further provides that when the living tissue structure is a blood vessel or duct, the structure is compressed within the collar so that fluid passage through the structure is impeded.
A method of joining surgical sutures together in a knotless weld comprises the steps of providing a fusible collar as described above, and encircling the sutures to be joined with the collar. The collar is then compressed around the sutures to retain them securely and to cause portions of the collar to overlap. Energy is applied to the overlapped portions of the collar to fuse those portions together, as well as to fuse portions of the collar to portions of the sutures.
These and other objects and advantages of the invention will in part be obvious and will in part appear hereinafter. The invention accordingly comprises the apparatus possessing the construction, combination of elements and arrangement of parts which are exemplified in the following detailed disclosure, the scope of which will be indicated in the claims.